More work is needed to explain the findings, but the researchers suspect a two-way relationship underpins the results. In this scenario, people with better thinking skills are more likely to use digital devices, but there are also cognitive benefits to be had from embracing the technology.
There’s a causality issue here.
It’s using speakerphone and FaceTime in public that causes lower rates of cognitive loss
Those aren’t the typical senior smartphone habits at all. (What even does using speakerphone matter?)